The invention relates to a control unit for controlling a start-up process of a vehicle power plant in a motor vehicle.
In principle, the vehicle power plant, which is usually designed as an internal combustion engine, is started by the driver of the vehicle. To this end, a key, which is provided for this purpose, is inserted into a corresponding lock, and this key is rotated in order to start the internal combustion engine; or an existing push button for activating the internal combustion engine is activated. In response, corresponding measures for starting the internal combustion engine are initiated. Such a start-up process of the internal combustion engine is referred to as the “normal start” or the “key start.”
In order to reduce fuel consumption and pollutant emissions, the current trend is to develop methods and systems (and to some extent they have also been already installed) that automatically switch-off the electric motor, the hybrid engine or the internal combustion engine, thus, the power plant of a motor vehicle, under certain conditions and/or in the presence of defined shut-off conditions and automatically re-start the electric motor, the hybrid engine or the internal combustion engine in the presence of defined start-up conditions. Such methods and systems are suited, above all, for urban traffic, in order to reduce the consumption of fuel and simultaneously also to reduce emission, above all, also for reducing the CO2 emission. This is because in urban traffic the vehicle often comes to a standstill at traffic lights or owing to the traffic and because it is not necessary to run the internal combustion engine. Such a start-up process of the internal combustion engine is referred to as the “automatic start.” Similarly, such a shut-off is referred to as the “automatic stop.”
The methods and control units for automatically shutting off or starting up a drive unit, that is a vehicle power plant, can be used in a number of different vehicle functions. Thus, for example, within the scope of a so-called “automatic start and stop function” the vehicle power plant is shut-off and also re-started again as a function of the predetermined conditions and in certain traffic situations, for example, at traffic lights or in so-called stop and go traffic. Similarly in the case of vehicles, which are equipped with a hybrid drive unit, consisting of an internal combustion engine (that is, an internal combustion engine with combustion that runs according to the thermodynamic processes of the Otto engine, diesel engine or similar designs) and an electric motor, this internal combustion engine is partially shut-off and started-up again, in order to save fuel and to reduce emissions.
One possibility for designing such methods and systems of the aforementioned type is the automatic shut-off and start-up control device, which is disclosed in DE 101 61 343 A1 and intended for an internal combustion engine. In this case, the control device implements appropriate measures for shutting off the internal combustion engine, when all of the shut-off conditions are met. If the predetermined start-up conditions are satisfied, the control device initiates the appropriate measures for automatically starting up the internal combustion engine.
Under some circumstances it can happen that in vehicles, which are equipped with an automatic shut-off and start-up device, owing to an active shut-off inhibiting condition (for example, the charge state of the battery is below a predetermined limit value), the automatic shut-off process of the internal combustion engine is not carried out. However, this omission is incomprehensible to the driver. Analogous thereto, it can also happen that owing to an active start-up inhibiting condition (for example, the fill level of the vehicle tank is below a predetermined limit value), there is no automatic start-up process. Similarly, this omission is also incomprehensible to the driver. In order to be able to ascertain the cause of such “errors,” the still unpublished DE 102007009836 proposes a control unit for controlling an automatic shut-off and/or start-up process of a vehicle power plant. In this case, the control unit sends to a memory unit a memory signal for storage of at least one memory entry, which is assigned to a shut-off inhibiting condition, when all shut-off request conditions are, in fact, fulfilled, yet at the same time at least one shut-off inhibiting condition is active, and, therefore, the vehicle power plant is not shut-off. Under some circumstances it is possible to determine with the memory entry, which can be read out by a readout device, the cause that was responsible for the omitted automatic shut-off process. Analogous thereto, the memory entries can also be made, when an automatically requested automatic start-up process is not initiated.
As soon as a start-up process of the internal combustion engine is requested in a vehicle, either manually by the driver or automatically owing to predetermined start-up conditions (without any start-up inhibiting condition being fulfilled), commensurate measures for starting up the internal combustion engine are initiated. These measures can be designed in a number of different ways as a function of the type of start-up request.
Under some circumstances, it can happen that the start-up of the internal combustion engine from the beginning of the start-up process, for example, from the beginning of a start trigger, set by the driver, up to the completion of a successful start takes longer than is expected by the driver. This discrepancy could lead to customer irritation or even to customer complaints.
Therefore, the object of the invention is to make such customer complaints more comprehensible at least for the personnel of the automotive service center.
This object is achieved by a control unit for controlling a start-up process of a vehicle power plant in a motor vehicle, wherein in response to a start-up request, the control unit emits a start-up signal for initiating corresponding start-up measures for starting up the vehicle power plant, and the control unit sends to a memory unit a memory signal for storage of at least one memory entry, if predetermined conditions are fulfilled. The control unit determines a time duration from the beginning of the start-up process up to the completion of a successful start-up process and sends, as a function of the determined time duration, a time duration dependent memory signal to the memory unit, and that the memory unit makes a time duration dependent memory entry. A readout unit is provided for reading out the memory entries of a memory unit, wherein the memory entries are time duration dependent memory entries, type dependent memory entries, kilometer reading dependent memory entries, and/or cause dependent memory entries. Advantageous further developments are described herein.
Therefore, the fundamental idea is to make it possible to measure the aforementioned time duration and to make it possible to evaluate the time duration by the personnel of the automotive service center by providing a memory unit in which information is stored that explains that, and why, the start-up process of the internal combustion engine did not take place within the conventional time duration.
With respect to controlling a start-up process of a vehicle power plant, in particular an internal combustion engine, the control unit determines the time duration of the start-up process, thus, from the beginning of the start-up process up to the completion of a successful start-up, and sends, as a function of the determined time duration, a time duration dependent memory signal, which can be the time duration itself, to an existing memory unit, which thereupon makes a corresponding time duration dependent memory entry. In this context, the memory unit can be a component of a memory unit, which is present in any event, and whose memory entries can be read out with suitable readout devices in the automotive service centers.
As already stated in the introduction, the start-up process can be activated by manual activation of a suitable operator control element or can be activated automatically, for example, within the framework of a so-called automatic start and stop system. As soon as the start-up request for starting-up or rather for starting-up the drive unit is on hand or this start-up request is determined on the basis of a corresponding algorithm inside the control unit, this control unit sends a start-up signal, which can consist of one or more signals, to the corresponding actuators. At the same time as soon as a start-up request is on hand, a timer is started. This timer determines the time duration of the start-up process. That is, the timer is stopped, as soon as a predetermined, uniform (idle) speed of the drive unit is reached. As a function of the determined time duration, a time duration dependent memory signal, which is a measure for the time duration, is sent to the memory unit. Thereupon, the memory unit makes a time duration dependent memory entry, which in turn gives information about the time duration required for the start-up process. Ideally, the memory unit stores the determined time duration of at least the last start-up process in a time duration memory unit. However, it is also possible to enter a predetermined number of the last determined time duration dependent memory entries, which can be continuously overwritten.
Since the driver, or rather the person who reads out the memory, is really interested in only the entries that are entered on the basis of a start-up process that lasts too long, an advantageous embodiment of the invention can send the time duration dependent memory signal, for example, only if the determined time duration exceeds a predetermined first time duration limit value or rather a time duration dependent memory entry can be made, only if the determined time duration exceeds a predetermined first time duration limit value. In this context, this first time duration limit value should be selected in such a manner that it matches approximately the time duration of a successful (fast) start-up process.
In addition or as an alternative to the time duration memory unit, in which a measure for the time duration of at least one start-up process is stored, the memory unit can be equipped with one or more counting units. Each counting unit can store the number of start-up processes with a specific time duration. That is, each counting unit is assigned a specific time frame, within which the determined time duration of the start-up process can lie. Thus, for example, the number of start-up processes with a normal time duration, with a longer time duration and with an extremely long time duration can be stored. To this end, the inventive memory unit in an advantageous embodiment is equipped in such a manner that in response to the time duration dependent memory signal this memory unit increases by one the value of an existing first counting unit, if the determined time duration or rather the time duration dependent memory signal allows one to detect that the determined time duration is not greater than a predetermined first time duration limit value. Analogous to the above, this first time duration limit value can be predetermined, or rather selected, in such a manner that it matches approximately the time duration of the successful (fast) start-up process.
Analogous to the first counting unit, the memory unit can be equipped with a second counting unit, whose value is increased by one, if the determined time duration is greater than the predetermined first time duration limit value and is not greater than a predetermined second time duration limit value. In this context, the second time duration limit value should be greater than the first time duration limit value by a certain time period.
Analogous to the first and second counting units, the memory unit can be equipped, in addition or as an alternative, with a third counting unit, whose value is increased by one, if the determined time duration of the start-up process is greater than the predetermined second time duration limit value.
If the vehicle is equipped in such a manner that the start-up request can be generated by different measures and/or if the start-up process can be initiated optionally by different measures, then it is practical to make additionally an entry in the memory unit. The entry indicates what type of start, for example, normal start or automatic start, was effected during the determined time duration.
Therefore, in an advantageous embodiment of the invention, the control unit can send additionally a type dependent memory signal to the memory unit, and the memory unit can make a type dependent memory entry. Analogous to the different counting units, a plurality of type memory fields can be provided advantageously. In this context, the type memory field, in which the current value of the type dependent memory entry is supposed to be entered, is in turn predetermined by the determined time duration. The type dependent memory entry is entered advantageously in a predetermined first type memory field, if the determined time duration is not greater than a predetermined first time duration limit value. If the determined time duration is greater than the predetermined first time duration limit value and is not greater than a predetermined second time duration limit value, then the type dependent memory entry is entered in a predetermined second type memory field. If the determined time duration is greater than the predetermined second time duration limit value, then the type dependent memory entry is entered in a predetermined third type memory field. At the same time, the type memory fields can be constructed in such a manner that they can store a predetermined number of previous type dependent memory entries.
In addition to the determined time duration, the counting entries and the type dependent memory entry, it is also possible to make additionally other memory entries. For example, a distance (kilometer or mile) reading dependent memory entry could also be made. In this case, the distance reading dependent memory entry is entered as a function of the distance reading while determining the time duration, thus during the corresponding start-up process.
If a start-up process is started and its time duration is determined, then the current distance reading, e.g., in kilometers or miles, is additionally recorded. The control unit sends, in addition to the time duration dependent memory signal, a distance reading dependent memory signal to the memory unit. Thereupon the memory unit makes a distance reading dependent memory entry. The distance reading dependent memory entry can be, for example, the currently determined distance reading of the vehicle.
Analogous to the different counting units and the type memory fields, a plurality of distance reading memory fields can also be provided advantageously. In this context, the distance reading memory field, in which the current value is supposed to be entered, is in turn predetermined by the determined time duration. The distance reading dependent memory entry is entered advantageously in a predetermined first distance reading memory field, if the determined time duration is not greater than a predetermined first time duration limit value. If the determined time duration is greater than the predetermined first time duration limit value and is not greater than a predetermined second time duration limit value, then the distance reading dependent memory entry is entered in a predetermined second distance reading memory field. If the determined time duration is greater than the predetermined second time duration limit value, then the distance reading dependent memory entry is entered in a predetermined third distance reading memory field. At the same time, the distance reading memory fields can be constructed in such a manner that they can store a predetermined number of previous type dependent memory entries.
If the determined time duration of the start-up process is greater than a predetermined first time duration limit value (that is, the start-up process has lasted longer than is to be expected with this type of start-up process), then the cause can be determined additionally in an advantageous embodiment of the invention. This cause is used by the personnel of the automotive service center as the working basis. Then the control unit sends, together with the determined time duration, a cause dependent memory signal to the memory unit, which thereupon makes a corresponding cause dependent memory entry. In so doing, the cause dependent memory signal and/or the cause dependent memory entry can be configured as a so-called bit word having a predetermined length, where the length of the bit word can be predetermined by the number of determinable causes. If a cause is determined, the value of the bit, assigned to this cause, is set to one, otherwise, it remains zero.
As an alternative, the cause dependent memory entry can also be configured in such a manner that, when a certain cause occurs, a cause counting unit, assigned to this cause, is increased by the value 1. In this way it can be determined at a later date, which causes are responsible especially often for a longer start-up process.
Analogous to the different counting units, the type memory fields, and the distance reading memory fields, a plurality of cause memory fields can be provided advantageously. In this context, the cause memory field, in which the current value is supposed to be entered, is in turn predetermined by the determined time duration. Thus, the cause dependent memory entry is entered in a predetermined second cause memory field, if the determined time duration is greater than a predetermined first time duration limit value and is not greater than a predetermined second time duration limit value. If the determined time duration is greater than the predetermined second time duration limit value, then the cause dependent memory entry is entered in a predetermined third cause memory field. At the same time the cause memory fields can be constructed in such a manner that they can store a predetermined number of previous cause dependent memory entries.
If, in addition to the time duration dependent memory entries, there are a plurality of other memory entries that are to be made and that are entered as a function of the time duration in different memory fields, then the limit values for determining the respective memory fields are predetermined in an identical way ideally for all memory entries.
In the case of the causes that can lead to a prolonged start-up process, it may concern a variety of causes. Correspondingly, the cause dependent memory entry can depend, for example, on the following (determinable) causes, which may occur individually or in combination and can be the cause for a delayed start-up:
(a) The current ambient/outside temperature is less than a predetermined minimum temperature value or is greater than a predetermined maximum temperature value.
(b) There is a mechanical or electrical error or also a combination of a mechanical and an electrical error in the fuel system.
(c) There is a mechanical or electrical error or also a combination of a mechanical and an electrical error in the fuel supply system.
(d) There is a mechanical or electrical error or also a combination of a mechanical and an electrical error in the high pressure pump system.
(e) The current tank content is less than a predetermined minimum tank content.
(f) There is a mechanical or electrical error or also a combination of a mechanical and an electrical error in the starter/start-up system.
(g) There is a mechanical or electrical error or also a combination of a mechanical and an electrical error in the battery system.
(h) The charge state of the battery is less than a predetermined minimum charge state, or the battery is damaged or has aged.
(i) There is a mechanical or electrical error or also a combination of a mechanical and an electrical error in the crankshaft synchronization system.
(j) There is a mechanical or electrical error or also a combination of a mechanical and an electrical error in the cam shaft synchronization system.
(k) There is a mechanical or electrical error or also a combination of a mechanical and an electrical error in the system of the (electronic) immobilization device and/or the anti-theft system, where this anti-theft function can also be included in other (electronic) control units that are integrated into the system with the (electronic) control unit. Such a combined system is also characterized by a possible communication of the (electronic) control units among each other.
(l) There is a mechanical or electrical error or also a combination of a mechanical and an electrical error in the vehicle access system, whose (electronic) control unit is capable of initiating the start-up of the vehicle power plant in response or according to the customer's request. This start function can also be included in other (electronic) control units, which are integrated into the system with the (electronic) control unit. The system can also include other (electronic) control units, which are integrated into the system with the (electronic) control unit. Such a combined system is characterized by a possible communication of the (electronic) control units among each other.
(m) The current ambient/outside pressure of the air is less than a predetermined minimum pressure value or is greater than a predetermined maximum pressure value.
(n) There is an error in the generator communication.
Depending on the size of the memory unit, it is practical to determine a specific number of causes or rather to make only specific cause dependent memory entries.
In order to be able to access the memory entries, the invention includes, besides the control unit, additionally a readout device, which can be connected to the memory unit and which is designed such that the memory entries, which are entered into the memory unit, can be read out and optionally evaluated.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.